Piston-valve.



1S, which are so located as to uncover the main steam ports 14a at the same time that the inner ends ot the pistons uncover the auxiliary ports 15a, as will be clearly seen from an inspection ot the righthand end of Fig. 1. Each piston is 4provided intermediate the ports 1S and the inner edges thereof with a shallow and con'iparatively wide groove forming a circumferential port 19, the width of this groove being sutiicientto connect the auxiliary steam portsl and auxiliary exhaust ports 1Ga during a predetern'lined portion ot the stroke, will be clearly seen from the lett hand end ot Fig. 1.

The pistons are so arranged with respect to the ports of the bushing that when the engine piston 2O at the end o its strol'e and ready for tle return stroke, both the auxiliary and main steam passages will be open to permit flow of steam in trent of vthe piston, and at the same time both the auxiliary and main exhaust ports will be uncovered at the opposite end of the valve. The tiow of live steam from the inlet passage 12 is through the ports 12 into the bushing, where the entire space betweenthe two piston heads l1 is filled. When the valve is in the position shown in Fig. `1, the steam escapes through the ports 1F, which are uncovered by the inner-end ot' the piston to the auxiliary` passage 15; The fiow is also through thebodyot the piston and through the ports 18 therein, which are in register with the ports 14a. As will be clearly seen from the drawings, the passage v15 discharges into the passage 14 a shortdistance outside of the engine cylinder 21. The steam rushing through these two passages mingles and is discharged through the engine cylinder ports in a greater volume than would be the case if a single port were used. In the opposite end of the cylinder, the exhaust passes through the passages 14 and 15. The ports 1st are uncovered by the valve piston and the exhaust steam is there- 4fore free to tiow out through the ports 13,

The passage 19 formed in the valve piston connects the ports 15a and 1G", so that exhaust steam passes from the passage linto thev auxiliary exhaust .passage 16, from which it is discharged through the passage 23 formed in the body of the cylinder 5 into s the mainexhaust passage 13.

From the foregoing description, it will be easily understood that since two ports which are each preferably designed to permit the maximum steam llow are opened simultaneously for both inlet and exhaust steam, that the open port arca. will be just double the usual opening, so that a greater volume ot steam will enter the engine cylinder at the commencement ot the stroke. The arr-angement ot' the steam passages provides for the injection of the steam into the cylinder at great pressure, and at the same/time allows t'or the expansion ot exhaust steam, which travels through the same passages in the opposite direction so that conside `able economy is effected.

IIaving thus described my invention, what I claim is A l. In a piston valve,'`a live steam main port leading from the valve chalnber to the engine cylinder .at one extremity of the ralre chamber, an auxiliary live stean port leading trom near the 'center of the valve chamber into the main steam port at the end of the valve chamber, a main exhaust port beyondthe main steam port, au auxiliary exhaustport. intermediate the main and auxiliary steanrports, anda valve piston having a passage' :formed therein connecting the auxiliary steam and exhaust ports at the same time that the body oit the piston uncovers the main steam and exhaust ports, and a passage coimecting the auxiliary and main exhaust ports.

Q. In apiston valve, a chamber, a plurality ot pistons having a reduced portion intermediate their extremities, said pistons reciprocating in said chamber, primary inlet and exhaust ports at each extremity ot the chamber, auxiliary inlet and exhaust ports intermediate said primary inlet and exhaust ports, the auxiliary exhaustports communicating with the primary exhaust ports by passing around the reduced portion the cylinders, and the auxiliary inlet ports communicating with the primary inlet ports through a passage in the. wall of the chambei-.

8. In combination with an engine cylin* der, piston valve comprising a chamber, a plurality ot hollow pistons having an intermediate reduced portion reciprocating in said chamber, primary exhaust and inlet ports at each extremity of the chamber and communicating with the engines cylinder, auxiliary exhaust and inlety ports intermediate the primary exhaust and inlet ports, said auxiliary exhaust ports coimuunicating with the primary exhaust ports through the medium ot the reduced portion of the pistons, and a passage in the wall lot the chamber, and the auxiliary inlet communicating with the primary inlet port by means of a passage through the wall of the chamber.

11. In combination with an engine cylinder, a pistou valve comprising a chamber, a plurality of open ended pistons provided with steam ports reciprocating in said chamber and each provided with a reduced portion, a main steam supply located centrally of said chamber and discharging into the open end of each of said open ended pistons, a primary and auxiliary port at each extremity of the chamber, said ports adapted to act alternately as supply and eXhanSt ports, the auxiliary ports communiczliling with the interior of the pistons when supplying steam to the engine cylinder, und communicating with the reduced p0rtion of the piston when exhausting Steam therefrom, und said primary ports communicating with the interior of the pistons when snppiying steam to the engine cylinder, und discharging directly into the exhanst port of the chamberlwhen exhaust- 10 ing steam fromithe engine cylinder.

In witness whereof I have hereunto set iny hand in the presence of two Witnesses.

Y FREDERICK A. BARTRAM.

Witnees:

STUART R. IV, ALLEN, Gr. M. MORELAND. 

